Maine CDC Press Release

August 5, 2021

Maine CDC Investigates Four Recent Cases of Legionella in Bangor Area

Regular cleaning of shower heads, humidifiers, and water heaters reduces growth of bacteria

AUGUSTA — The Maine Center for Disease Control and Prevention (Maine CDC) has confirmed four recent cases of Legionella in the Bangor area. Maine CDC is actively investigating whether the cases are coincidental or if there is a common exposure among them. All four individuals were hospitalized.

Legionella, also known as Legionnaires' disease, is not spread from person to person. Maine CDC has alerted health care providers so they can consider testing for the illness, which could lead to the identification of additional cases. All cases must be reported to Maine CDC.

Legionella bacteria are found naturally in freshwater environments, such as lakes and streams. Legionella can become a health concern when it grows and spreads in human-made building water systems such as cooling towers used in air conditioning systems, hot tubs, fountains, and large plumbing systems. Legionnaires' disease, which is a type of pneumonia, may result when individuals breathe in droplets of water that contain the bacteria. Symptoms include cough, shortness of breath, fever, muscle aches, and headaches.

Most healthy people exposed to Legionella do not get sick. Those at increased risk of getting sick are people age 50 years and older; current or former smokers; people with a chronic lung disease, weak immune systems, or cancer; and people with underlying illnesses such as diabetes, kidney failure, or liver failure.

Doctors use chest x-rays or physical exams to check for pneumonia and may also order tests on a sample of urine and sputum (phlegm) to determine if a lung infection is caused by Legionella. Legionnaires' disease is treated with antibiotics. Most people who get sick need care in a hospital but make a full recovery. However, about 1 out of 10 people who get Legionnaires' disease will die from the infection.

Legionella cases have been on the rise in the United States since 2000. About 9,000 cases were reported in 2019. Maine has averaged 21.4 cases per year since 2016.

Steps to prevent growth of the bacteria include.

  • Flushing water heaters every year. This helps reduce the risk of bacteria growth. Electric water heaters are more likely than gas water heaters to have bacteria. Flushing should be done with caution by a qualified plumber.
  • Removing and cleaning shower heads. This can be done by soaking shower heads in a mixture of 1 tablespoon household bleach to 1 gallon of water for about two hours.
  • Regularly cleaning and disinfecting humidifiers: Always unplug the humidifier first. Clean the inside using a mixture such as 1 tablespoon household bleach to 1 gallon of water, and dry. Follow the manufacturer’s instructions for cleaning.
  • Regularly cleaning CPAP machines and nebulizers: Use distilled water only and clean regularly. Follow the manufacturer’s instructions for cleaning.

For more information on Legionella, visit: